But both Mr Morrissey and Doug Trapnell, SC, for the Office of Public Prosecutions, conceded in written submissions that neither side had asked that the jury be given this option during the trial.

Mr Morrissey submitted that the manslaughter verdict would have been open on the evidence, and the failure of trial judge Lex Lasry to invite the jury to consider it, amounted to a substantial miscarriage of justice.

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He also submitted that, if his arguments were accepted, the court should, in the ''oppressive circumstances of this case'', acquit Farquharson rather than order a retrial.

But Mr Trapnell submitted there was no viable manslaughter case - because the Crown's case was that Farquharson had ''consciously, voluntarily and deliberately'' driven his car into the dam with the intent to kill his sons - and therefore no need for the jury to consider it.

The other appeal ground was that Justice Lasry failed to adequately direct the jury about how to consider the account of a friend of Farquharson, who testified that Farquharson told him he would pay back his ex-wife ''big time''.

Farquharson was sentenced to life without parole after first being convicted of his boys' murders. He then received three life sentences with a minimum of 33 years' jail after the retrial.

He has maintained he had a coughing fit and blacked out at the wheel when his car careered off the road and into a 10-metre- deep dam at Winchelsea.

His ex-wife, Cindy Gambino, wept in court after the judgment was handed down. Outside court, her husband Stephen Moules said: ''We're very, very pleased with the outcome.''

The three judges rejected the defence's arguments, holding that it was ''reasonably open to the jury on the whole of the evidence to be satisfied beyond reasonable doubt of Mr Farquharson's guilt.

''The court said that it was for the jury, drawing on their experience of human behaviour, to evaluate the competing arguments,'' they said.

''The defence contended that it was extremely improbable that a father would murder his children. The prosecution contended that it was extremely improbable that a father who had accidentally caused the deaths of his children would behave in the way Mr Farquharson did.''

Farquharson's lawyers are now considering whether to seek leave to appeal to the High Court.